Salt Crystallization in Chitosan Films as Affected by Solvent pH and Moisture Content

摘要

Water sorption isotherms and mechanical properties of chitosan films prepared under different solvent conditions were significantly affected by ion concentration and pH. Increase in pH and ionic strength of the solvent led to an increase in the water sorption capacity of films, with a significant decrease in the resistance to break and the ability to stretch of chitosan films. The reported changes can be explained by the crystallization of sodium-acetate tri-hydrate in chitosan films prepared with solvent Ⅱ (pH = 5.2), which was revealed by the salt melting values obtained by DSC thermal analysis and film microstructure.